Fortunately Google's Panda has dramatically slowed down the growth for sites like Ranker. Google applies an extremely heavy penalty for using content from sites like Freebase and Wikipedia. If those penalties didn't exist, there's little question Ranker would be a top 1k site.

Other lame content theft sites like Mahalo have been practically put out of their misery.

I actually don't think they do; they're directly measured by quantcast. If you go to

http://www.quantcast.com/ranker.com

and select page views, week, and global they still peak at 4mm. Which is nothing to laugh at.